1. Field of the Invention
The present invention relates to heterocyclic compounds and organic light-emitting devices including the heterocyclic compounds.
2. Description of the Related Art
Organic light-emitting devices are self-emission type display devices and have wide viewing angles, high contrast ratios, and short response times. Due to these characteristics, organic light-emitting devices are drawing more attention.
Such organic light-emitting devices can be roughly classified into inorganic light-emitting devices which include emission layers containing inorganic compounds, and organic light-emitting devices which include emission layers containing organic compounds. Organic light-emitting devices have higher luminance, lower driving voltages, and shorter response times than inorganic light-emitting devices, and can render multi-colored displays. In addition, organic light-emitting devices produce various colors. Thus, much research into such organic light-emitting devices has been conducted.
Typically, an organic light-emitting device has a stack structure including an anode, a cathode and an organic emission layer between the anode and cathode. However, a hole injection layer and/or a hole transport layer may be further stacked between the anode and the organic emission layer, and/or an electron transport layer may be further stacked between the organic emission layer and the cathode. In other words, an organic light-emitting device may have an anode/hole transport layer/organic emission layer/cathode structure or an anode/hole transport layer/organic emission layer/electron transport layer/cathode structure.
As the material for forming the hole transport layer, polyphenyl compounds or anthracene derivatives can be used. However, organic light-emitting devices including hole injection layers and/or hole transport layers formed of such materials do not have satisfactory life span, efficiency, and power consumption characteristics, thus leaving much room for improvement.